Sea Drake — ruling 1

Although you must choose two lands you control as the targets of Sea Drake's triggered ability, there is no consequence to Sea Drake if the ability doesn't resolve. If one of the lands becomes an illegal target in response, the remaining legal target will be returned to its owner's hand. If both targets have become illegal in response, nothing happens.

Sea Drake — ruling 2

If you can't target two lands you control with the triggered ability (perhaps because you control fewer than two lands), the ability will be removed from the stack. You won't return any lands. There is no consequence for this.

Sea Drake : règles, fonctionnement et interactions (MTG)

Sea Drake is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Flying When this creature enters, return two target lands you control to their owner's hand.

How it works : Sea Drake

Original English text — Wizards of the Coast / Scryfall

#1June 18, 2021· Wizards of the Coast
Although you must choose two lands you control as the targets of Sea Drake's triggered ability, there is no consequence to Sea Drake if the ability doesn't resolve. If one of the lands becomes an illegal target in response, the remaining legal target will be returned to its owner's hand. If both targets have become illegal in response, nothing happens.
No other card is named in this ruling.
#2June 18, 2021· Wizards of the Coast
If you can't target two lands you control with the triggered ability (perhaps because you control fewer than two lands), the ability will be removed from the stack. You won't return any lands. There is no consequence for this.
No other card is named in this ruling.